Shisakajima Island

A group of islands in the Seto Inland Sea, Hiuchi Nada, northeastern Ehime Prefecture. Located 18 km north-northeast of Niihama City, it consists of the islands of Mino, Ieno, Kaji, Nezumi, and Myojin. Its total area is 1.26 square kilometers. It is part of Imabari City. The Sumitomo Besshi Copper Mine Smelter has been located here since 1895 (Meiji 28). The ore from the Besshi Copper Mine, which was developed during the Edo period, was smelted into crude copper at Besshiyama, Hadeba, and Sobiraki, but as production increased in the Meiji period, smoke pollution also increased. In 1895, Sumitomo bought the four uninhabited islands of Shisakajima, built a smelter on Ienoshima, converted Minoshima into a residential area, connected the two by reclaiming land, and began operations in 1905 (Meiji 38). However, the damage from sulfurous acid gas smoke spread to the four Toyo counties of Ochi, Shuso, Arai, and Uma, and restrictions were imposed on the amount of ore smelted and compensation payments were made, especially during the rice and wheat growing season. In 1930 (Showa 5), ​​a Petersen-type desulfurization unit was completed, and in 1939, a sulfur plant using the neutralization method was completed, and the air pollution problem was resolved. The smelter subsequently flourished as one of Japan's leading copper smelters, and by 1960 (Showa 35), the population had reached 3,700 and annual copper production reached 50,000 tons. The island had a clinic, a school, shops, and temples. The Besshi Copper Mine closed in 1973, and the smelter closed in 1976 due to the global copper mining recession, causing most of the residents to leave the island. Currently, there are no residents, but a factory that recovers zinc oxide from steelmaking dust is in operation, and some people commute to the factory by boat from Niihama Port.

[Kazuo Fukaishi]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

愛媛県北東部、瀬戸内海燧灘(ひうちなだ)に浮かぶ島嶼(とうしょ)。新居浜(にいはま)市の北北東18キロメートルにあり、美濃(みの)島、家ノ島、梶(かじ)島、鼠(ねずみ)島、明神(みょうじん)島からなる。総面積1.26平方キロメートル。今治(いまばり)市に属す。1895年（明治28）以来住友別子銅山製錬所(べっしどうざんせいれんじょ)が置かれた。江戸時代から開発された別子銅山の鉱石は別子山、端出場(はでば)、惣開(そうびらき)などで粗銅製錬が行われていたが、明治になって生産量が増加すると煙害が増加した。1895年住友は、無人島であった四阪島4島を買収し、製錬所を家ノ島に建設、美濃島を住宅地とし、両者を埋立てで連絡し、1905年（明治38）操業を開始した。しかし亜硫酸ガスの煙害はかえって被害地域を拡大し、越智、周桑(しゅうそう)、新居、宇摩(うま)の東予四郡に及び、製錬鉱量の制限や補償金の支払いがなされ、とくに米麦作期に強化された。1930年（昭和5）ペテルゼン式脱硫装置、1939年中和法の硫黄(いおう)工場が完成し、以降の大気汚染問題は解決した。その後同製錬所はわが国有数の銅製錬所として栄え、1960年（昭和35）には人口3700人、年間銅生産量5万トンに達し、島には診療所、学校、商店、社寺などがあった。1973年別子銅山の閉山、世界的銅鉱業の不況で、1976年同製錬所も閉鎖し、ほとんどの住民が離島した。現在、住民はおらず、製鋼煙灰から酸化亜鉛を回収する工場が操業していて、新居浜港から船で工場に通勤する人がいる。

［深石一夫］

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